Safety Group Proposes 3rd Stairwell In High-Rises

By ERIC LIPTON

Published: June 23, 2007

Skyscraper safety requirements proposed after the World Trade Center attacks on Sept. 11 have been adopted by the pre-eminent building code group. That means tall buildings nationwide could soon be required to be designed with an extra emergency stairwell and more robust fireproofing.

The changes, which would apply just to new construction, are being described by safety advocates as a major advance that could have meant fewer deaths on Sept. 11, 2001.

''Here is something that has been learned from what happened on 9/11,'' said Sally Regenhard, founder of the Skyscraper Safety Campaign, whose son Christian, a firefighter, was killed in the attacks.

Some building owners and designers are already protesting, saying the measures would unnecessarily add millions of dollars in costs.

''This is redundant and excessive,'' said David Collins, an architect in Cincinnati who is a consultant to the American Institute of Architects on building codes and standards.

Mr. Collins predicted an effort to pull back the measures even before cities and states moved to adopt them into their local codes.

The changes were approved by the International Code Council late last month as part its so-called model building code. These model codes do not have the force of law, but they are the blueprint that building officials in 47 states use to formulate their own codes.

The director of codes and standards in New Jersey, William M. Connolly, who helped draft the new provisions, predicted that they would be the norm nationally within several years.

''These are really important changes that will provide real benefits in terms of safety,'' Mr. Connolly said Friday.

The most significant change would be requiring a third stairwell in buildings taller than 420 feet, or about 35 stories. At least one elevator in buildings at least 120 feet tall would also have to be specially built with backup power systems and fire-resistant wiring so firefighters could use it reliably in emergencies.

Fireproofing for steel columns, to prevent a structural collapse, would have to be nearly three times stronger in high rises up to 35 stories and seven times stronger for even taller towers, making it less likely to fall off.

Building components with a role in the frame of a structure like the floors of the World Trade Center would also have to be able to withstand a fire as long as the main columns held up the building.

Stairwells would have to be lined with glow-in-the-dark markings, so occupants could leave even with the lights out.

None of these conditions, except for the luminous markings, are now part of the code in New York, even though the city's code is already stricter than the norm elsewhere.

The changes were recommended by the National Institute of Standards and Technology, which spent three years studying the World Trade Center collapse. The lead investigator, S. Shyam Sunder, said if the proposed measures had been in place, the twin towers, which already had three stairwells each, would have probably still collapsed. But they might have stood longer, allowing more occupants or rescue workers to leave.

Mr. Collins and Jon Magnusson, a structural engineer from Seattle, said the code improvements were unnecessary, as the two stairwells in most modern skyscrapers were sufficient.

''If they are actually saving lives, we should spend more money,'' Mr. Magnusson said. ''But with this, they are not going to provide real safety. They will just add costs.''

The requirement for the extra stairwell alone could add $4 million for a 70-story building, according to a rough estimate by a structural engineer in New York who insisted on anonymity because no formal analysis had been conducted.

Separate from these changes, New York is expected in coming weeks to adopt its version of the code of the International Code Council. But, a city official said Friday, it is unlikely that the new version will incorporate the latest round of changes until 2010.